ChemInform Abstract: Palladium‐Catalysed Coupling Reactions

Arylzinc reagents, prepared from aryl halides/zinc powder or aryl Grignard reagents/zinc chloride, were found to undergo coupling with aryl and alkenyl halides without the aid of transition‐metal catalysis to give biaryls and styrene derivatives, respectively. In this context, we have already reported the corresponding reaction using aryl Grignard reagents instead of arylzinc reagents. Compared with the Grignard cross‐coupling, the present reaction features high functional‐group tolerance, whereby electrophilic groups such as alkoxycarbonyl and cyano groups are compatible as substituents on both the arylzinc reagents and the aryl halides. Aryl halides receive a single electron and thereby become activated as the corresponding anion radicals, which react with arylzinc reagents, thus leading to the cross‐coupling products.

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Keywords: preparation; hexamethyl-trans-σ-trishomobenzene (2); preparation; olefins from vinyl halides and alkyllithiums; beckmann fragmentation of ketoximes; aryl- and vinyl-substituted acetylenes; dehydrobromination of α-bromo ketones; ketone synthesis; extrusion of mercury from bis(propenyl)mercury; allylation of amines; alkenes from vinyl iodides and grignard reagents; conjugated enynes; arylalkynes; unsymmetrical biaryls and diarylmethanes; vinyl nitriles; cyclization via π-allylpalladium complexes; steroid side chain; cyclization to medium-sized lactones; chiral methyl chiral lactic acid (5); isomerization of 1,3-diene epoxides; alkylation of vinyl lactones; reductive acylation of alkoxy-substituted allylic acetates; methylenecyclopentanes; stereospecific synthesis of alkenes; cross-coupling of aryl halides and 1-alkenylboranes; iboga alkaloids; isomerization and elimination of allylic acetates; supported reagent; coupling of allyl bromides and allylstannanes; decarboxylation of β-acetoxy carboxylic acids; cleavage of endoperoxides; alkylation of dihydropyranyl acetates; alkylation and amination of allylic phosphates; 1,4-Dienes; α-Allylated ketones; alkylation of allyl nitroalkanes; allylation of nucleophiles; alkylation of vinyl epoxides; vinylsilanes; nucleophilic substitution reactions with α-acetoxy-β,γ-unsaturated nitriles; macrocyclization; macroheterocyclization; β-Keto esters; double silylation; allylic sulfones; 2,3-Disubstituted bicyclo[2.2.1]heptanes; desulfonylation; homoallylic alcohols; sequential π-allylpalladium alkylation; biaryls; 1,3-Dienes; heterosubstituted 1,3-dienes; 1,3-Diynes; allenynes; coupling of vinyl triflates with organotins; acylation of organozinc reagents; β-Carboline synthesis; allylation of potassium enoxyborates; allylic amination; macrocyclization by allylation–alkylation; steroidal 6β-hydroxy-2,4-diene-1-ones; trans- cis-Cinnamic acids; RX RCHO; coupling of vinyl triflates with alkenes; α-Diketones; carbonylation of 1-iodo-1,4- and -1,5-dienes; conjugate reduction; denitro-sulfonylation; allylic sulfones; coupling of 1-alkenylboranes with 1-bromoalkenes or -alkynes; cross-coupling of organoalanes with allylic acetals or ortho esters; carbonylation; 1,4-diazepines; decarbonylative cross coupling of acyl halides; decarbonylation of acyl cyanides; allylation of lithium 1-cyclopentenolates; asymmetric allylation; bisethynylation of vic-dichloroethylenes; pyrrolidines; piperidines; unsymmetrical biaryls; primary allylic amines; coupling of aryl triflates with organostannanes; coupling of vinylboranes and vinyl halides; intramolecular heck reactions; hydroxylamination; denitration of allylic nitro groups; coupling of RCOCl with Bu4Pb; intramolecular arylation; cyclizative heck coupling; [3 + 2]Annelation; Pd-catalyzed intramolecular ene reactions; allylidenation of aldehydes; 3-Aza-Cope rearrangement; biphenyls; coupling of alkylsilanes with aryl triflates; (Z,E)-2-Bromo-1,3-dienes; alkenyl sulfides; ArOTf+AlR3 ArR; 1,2-Diene-4-ynes; indole synthesis; sulfones; carbonylation of aryl and vinyl iodides; benzylpalladation; intramolecular heck cyclizations; intramolecular ene reactions; coupling of 1-alkynes and vinyl halides; coupling of 2-bromonaphthoquinones with stannanes; addition of (ArS)2 and (ArSe)2 to 1-alkynes; coupling of acid chloride with (E)-Bu3SnCH CHSnBu3; 1,4-diketones; chiral oxazolines; stille carbonylative coupling; cyclization of triynes to benzenes; coupling of aryl iodides and arylboronic acids; allylic substitutions; allylation of carbonyl compounds and imines; coupling of organozincs with aryl halides; coupling of organozincs with alkenyl halides; coupling involving organoborons; coupling of organotins with unsaturated halides; destannylative acylation; coupling of organosilanes with aryl halides; cyclopropanation of norbornene; intramolecular zinc-ene reaction; deallylation; stille coupling; suzuki coupling; other cross-couplings; carbonylations; allylic substitutions; rearrangements; cycloadditions; hydrogenation; allyl and propargyl group transfer; suzuki coupling; intramolecular coupling of phenols with haloarenes; stille coupling; other reactions of organostannanes; negishi coupling; carbonylative coupling; arenes from enynes and diynes; cyclization; rearrangement; allylic displacements; tandem coupling and cyclization; cyclizations and cycloadditions; addition to alkynes; acylations; stille coupling; suzuki coupling; other coupling reactions; rearrangements; addition reactions; substitution reactions; coupling reactions; acylation and allylation; 2-pyridylpyrroles; coupling reactions; decarboxylative transformations; allylation; cyclizations; additions; cycloadditions; deprotection; coupling reactions; heterocycle synthesis; cleavage of C—O bonds; cyclization; cycloaddition; aminocarbonylation; addition; substitution; coupling reactions; isomerization; tetrabutylammonium fluoride, TBAF; tetrabutylammonium difluorotriphenylsilicate; tetracarbonylhydridorhenium; titanocene bis(triethyl phosphite); trimethylsilyl trifluoromethanesulfonate

Palladium-catalyzed reaction between aryl or alkenyl halides and (1-carbalkoxy-1-alkenyl)zinc iodides. A new class of unmasked β-substituted acrylate α-anion equivalents

CuO/AB was found to be a simple and efficient catalyst for the N-arylation of a variety of nitrogen-containing heterocycles, giving the products in excellent yields.

In this project palladium (0) S-methylisothiourea was grafted into MCM-41 mesoporous silica. Palladium (0) S-methylisothiourea complex supported on MCM-41 (Pd(0)-SMT-MCM-41), as heterogeneous and reusable catalyst, was used in C–C bond formation between various aryl halides with sodium tetraphenylborate or phenylboronic acid (Suzuki reaction), aryl halides with triphenyltin chloride (Stille reaction), and aryl halides with styrene or n-butyl acrylate (Heck reaction). This catalyst was characterized by various physico-chemical techniques such as X-ray diffraction, transmission electron microscopy, scanning electron microscopy (SEM/EDX), thermal gravimetric analysis (TGA/DTA), fourier transform infrared spectroscopy and inductively coupled plasma. The results indicated that Pd(0)-SMT-MCM-41 catalyst could be easily recovered from reaction mixture for several consequence runs without significant loss of its catalytic activities.

Synthesis and characterization of palladium nanoparticles immobilized on graphene oxide functionalized with triethylenetetramine or 2,6-diaminopyridine and application for the Suzuki cross-coupling reaction

Two different combinations of coupling partners can be employed for the synthesis of conjugated dienes by palladium‐catalyzed cross‐coupling with tosylhydrazones: α,β‐unsaturated ketone and aryl halide or alkenyl halide and non‐conjugated tosylhydrazone. Depending on the substrate, a vinylogous hydride elimination is responsible for the formation of the final dienes.

Comprehensive SummaryOrganofluorine compounds have attracted substantial interest in life and materials sciences due to the unique properties of fluorine atom(s) that often change the physicochemical and biological properties of organic molecules. Transition‐metal‐mediated cross‐electrophile coupling between carbon electrophiles and fluoroalkyl electrophiles has emerged as a straightforward and efficient route for the synthesis of a wide range of fluoroalkylated compounds because of its synthetic convenience without the tedious synthesis of organometallic reagents. Moreover, alkenes or alkynes‐involved three‐component cross‐electrophile couplings provide rapid and effective access to carbonfunctionalized fluoroalkylated alkanes and alkenes. Herein, we comprehensively summarize the transition‐metal‐mediated reductive fluoroalkylation of diverse carbon electrophiles through a historical perspective, including trifluoromethylation, difluoroalkylation, monofluoroalkylation, and so on. Different transition metals (Cu, Ni, etc.) and strategies are discussed, in which nickel‐catalyzed reductive fluoroalkylation reactions represent an attractive and efficient synthetic route to site‐selectively access organofluorine compounds. Key ScientistsAs early as 1965, McLoughlin and Thrower finished the first stoichiometric copper‐mediated fluoroalkylation of aromatic iodides with fluoroalkyl iodides. However, excess aromatic iodides and elevated temperature were used for this method. In 1969, Kobayashi and Kumadaki reported studies on the copper‐mediated trifluoromethylation of aromatic halides with excess trifluoromethyl iodide. After more than four decades, the Zhang group developed a nickel‐catalyzed β‐fluorinated alkylation of (hetero)aryl iodides with fluoroalkylated secondary alkyl bromides in 2015, and a nickel‐catalyzed difluoromethylation of (hetero)aryl chlorides with chlorodifluoromethane ClCF2H in 2017. The Zhang group also developed enantioselective nickel‐catalyzed reductive alkyl‐arylation of 3,3,3‐trifluoropropene with (hetero)aryl and tertiary alkyl iodides. In 2018, the MacMillan group developed a novel copper/photoredox dual catalytic system for the trifluoromethylation of aryl bromides or alkyl bromides with (S)‐(trifluoromethyl) dimesitylsulfonium triflate in the presence of tris‐(trimethylsilyl) silanol. They also developed a nickel/photoredox catalyzed difluoromethylation of aryl bromides in the presence of silane. During this time, the Wang group reported a nickel‐catalyzed monofluoroalkylation of aryl halides with monofluoroalkyl halides. From 2021 to 2023, the same group further developed a series of enantioselective nickel‐catalyzed trifluoroalkylation of aryl, alkenyl, and acyl halides. Moreover, nonfluorinated alkenes or alkynes could also be used in three‐component cross‐electrophile couplings. In 2018, the Chu group reported a nickel‐catalyzed fluoroalkyl‐acylation of alkenes with acyl chlorides and fluoroalkyl iodides. Later, they developed a nickel‐catalyzed enantioselective fluoroalkyl‐arylation of unactivated alkenes tethering with a pendant chelating group. In 2019, the Chaładaj group reported a palladium‐catalyzed reductive perfluoroalkyl‐arylation of alkynes with perfluoroalkyl and aryl iodides.

Palladium(II)‐catalyzed N‐acylation was demonstrated through the reaction of N−H sulfoximines with a variety of aryl, heteroaryl, and aryl halides using W(CO)6 as a source of carbon monoxide, affording N‐acylated sulfoximines in good to excellent yields. Moreover, alkenyl bromides underwent palladium(II)‐catalyzed N‐acylation reactions with N−H sulfoximines, leading to the formation of N‐cinnamoyl sulfoximines. This method has the advantages of a broad substrate scope, high functional group tolerance, simple operation, and chemoselectivity between chloride and bromide.

The Suzuki coupling represents a widely used method for the synthesis of biarylic compounds 1 and has been already applied on industrial scale. Unfortunately, for a long time this reaction was limited to the use of aryl bromides, aryl iodes or electron-deficient aryl chlorides as starting materials. Thus, a general approach to the desired biarylic compounds 1 using the cheap and easy available aryl chlorides has not been available. In the last two years, however, several new protocols for the Suzuki coupling with aryl chlorides have been developed. These methods allow an efficient synthesis of biaryls of type 1, independently of the substitution pattern and electronic properties of the starting materials. These concepts which have been developed by the research groups of Fu, Buchwald, Guram, Beller as well as Trudell and Nolan are highlighted in this review.

1,1′-Binaphthyl derivatives 1-5, substituted in the 2- or 2,2′-positions are used in palladium-catalyzed Suzuki coupling reactions. The mono- and bis-borylated coupling components 2, 4 and 5 can easily be prepared and purified, are air-stable and are therefore interesting starting materials for Suzuki coupling reactions with several aryl halides. Thus a variety of new axially-chiral 2- and 2,2′-arylated 1,1′-binaphthyls can be synthesized. Selective monoarylation of 3, 4 and 5 can be performed. Subsequent and stepwise arylation offers general access to unsymmetrically substituted binaphthyls. Moreover, interesting atropisomeric complex molecules, such as 4,4′-bis[2-(1,1′-binaphthyl)]-1,1′-biphenyl (18a), are accessible. Compounds of type 18, which can be obtained by twofold Pd-catalyzed coupling reactions, are of high potential value as ligands or promoters in catalytic, asymmetric processes or as chiral precursor molecules for host-guest interactions.

Novel palladium (II)-containing polyimides with exceptional catalytic properties for the Heck and Suzuki–Miyaura cross-coupling reactions were prepared from Pd(II)-α-bis(imine) complex and the corresponding dianhyrides. The glass transition temperatures (Tg) of the polymers ranged from 169 to 241°C. The temperatures at which 10% weight loss occurred in air ranged from 415 to 579°C. Polyimides based on the palladium (II) complex were tested for catalytic activity in the Heck coupling reaction between styrene and several aryl halides and the Suzuki coupling reaction between phenylboronic acid and several aryl halides. The negative effects (e.g., expense, low reaction rates, air-sensitivity) experienced by using phosphines, particularly electron-rich phosphines, as catalysts in large scale applications is overcome by using polymer supported catalysis.

A palladium-catalyzed cyclization-carbonylation-coupling reaction between aryl halides and γ-Hydroxyallenes to form aryl (tetrahydrofuran-2-yl)vinyl ketones

Highly efficient and simple coupling reactions of benzylic and aryl bromides with aluminium acetylide catalyzed by NiCl(2)(PPh(3))(2) are reported. The coupling reactions proceed at room temperature employing 4 mol% catalyst, affording coupling products in excellent yields of up to 95% in short reaction times. The system worked efficiently with aryl and heterocyclic bromides as well.

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